Sintering 

and Desulphurizing of 
Iron Ore Materials 



American Ore Reclamation 

Company 





Copyright 1919 

V A " lerican °r« Reclamation Co. 


CtQ 

Oil 


161919 





American Ore Reclamation 

Company 




Sample of Sintered Material Showing Cellular Character 

of Product. 


/ 




y 


“A chemical action can only take place between two 
bodies, however great their affinity, it they are in intimate 
contact with each other; and the rapidity of this action 
will he so much greater, the more numerous the points 
of contact are/ 






Main Office: 71 Broadway, New York City 

Chicago Office: 

American Sintering Company * Railway Exchange Buildin 





Microphotographs 



PUDDLE CINDER 

Magnified 40 Diameters 

Cooled from Liquid State and Crys¬ 
talline. Large Excess Light Colored 
Ferro-silicates. No Cellular Structure. 


ROTARY KILN NODULES FROM 
FLUE DUST 

Magnified 40 Diameters 

Cooled After Complete Fusion and 
Crystalline. Large Excess Light Col¬ 
ored Ferro-silicates. Note Similarity 
to Puddle Cinder. No Cellular 
Structure. 



SINTER FROM FLUE DUST ''' 


Magnified 40 Diameters 


Complete Absence of Light Colored 
Ferro-silicates. Whole Mass Dark 
Opaque Iron-oxide. No Crystals and 
Only Slightly Fused. Cellular Struc¬ 
ture Fully Developed. 



SINTER FROM GRANULAR 
HEMATITE ORE 

Magnified 40 Diameters 

Traces of Light Colored Ferro-silicates. 
Larger Part of Mass Dark Opaque 
Iron-oxide. Few Crystals and Only 
Slightly Fused. Cellular Spaces 
Pred ominate. 


©C1A533546 


Page Two 














American Ore Reclamation Company 

T HE American Ore Reclamation Company is engaged in 
the licensing and engineering of plants for the sintering 
and desulphurizing of iron bearing material, and acts as 
consulting engineers with respect to the treatment of iron ore 
material that can be beneficiated by sintering. 

1 he Company operates principally under the Dwight & 
Lloyd patents for continuous down-draft sintering, and is also 
licensed to use the intermittent process of sintering with sepa¬ 
rate tilting pans, the Heberlein up-draft process, and the 
rotary kiln, which represent a total of 52 patents covering 
the art of sintering. 

Sintering is a comparatively recent art in the iron in¬ 
dustry. It is the process of agglomerating hue ore material 
into a mass that is suitable for blast furnace use. Sintering 
may be illustrated as the making of flour into biscuits. With 
the use of the fine ores from the Mesaba Range in Minnesota 
and the resulting increase in make of flue dust at blast fur¬ 
naces, many attempts were made to reclaim the valuable iron 
in the flue dust by briquetting. This means of treatment has 
not proven very satisfactory since to secure a firm bond the 
process is expensive, and when the bond is fickle the bri¬ 
quettes quickly return to dust. 

The briquette is a porous mass and the spaces are filled 
with air, so that the mass must be heated to first expel the 
air to allow the reducing gases of the furnace to come in 
contact with the ore particles, which delays the reduction, 
and the mass is easily disintegrated into dust. Sinter, made 
by the continuous down-draft process, is cellular in structure, 
providing an open and large area of contact between ore and 
reducing gases; and as the cell walls are quickly heated to 
the temperature required for reduction, an economy in coke 
consumption results from the use of sinter. 

To quote Schinz’s law (in his “Action of the Blast Fur- 


I’age Three 


American Ore Reclamation Company 



High Type 


of Sintering Plant With Overhead 
Steel Construction. 


Storage 


Bins. 


Page Four 


















American Ore Reclamation Company 


nace ’) : “A chemical action can only take place between two 
bodies, however great their affinity, if they are in intimate 
contact with each other; and the rapidity of this action will 
be so much greater, the more numerous the points of contact 
are.” The material which provides the greatest area of 
contact is more readily and economically reduced in the 
furnace. 

The iron bearing materials treated by sintering include 
blast furnace flue dust, roll scale, magnetic concentrates, 
magnetic sands, high sulphur ore, pyrites cinder, Mayari 
ore, Mesaba Range Paint Rock, ore washery fines, etc. Any 
finely divided ore or ores containing high sulphur or high 
moisture and combined water can be converted into ideal 
material for use in the blast furnace. Flue dust sludge from 
blast furnace gas washers may be sintered by adding the 
sludge to a dry sintering mixture, instead of moistening the 
charge with water. 

Sintering was first applied in the iron industry to the 
reclamation of flue dust, but it has since widened out into 
other fields and demonstrated its adaptability for treating 
pyrites cinder, magnetic ore concentrates and other fine ores 
or hydrated ores. 

Through the country there are vast fields of low grade 
magnetic ore which can now be cheaply concentrated and by 
subsequent sintering is converted into an ideal ore, rich in 
iron for use in the furnace. Magnetic ore in the massive state 
is penalized in price in the ore market, not because it is 
magnetic oxide but on account of its compact structure, while 
sinter made from magnetic concentrates is no longer massive 
but open and cellular in structure, and deserves a preference 
for furnace use as compared with natural ores. 

Silicate of iron, which composes heating furnace cinder 
and is difficult to reduce in the blast furnace, does not occur 
in the sinter produced by the continuous down-draft method. 


Page Five 



American Ore Reclamation Company 



General Description of a Sintering Plant 

A PLANT installation is made up of two main parts: the 
sintering machine proper and the raw materials plant, 
both forming a unit, of which the former is more or 
less standardized, but the latter made to conform to local 
conditions and materials. The following is a description of 
a typical plant. 

The materials to be sintered are delivered into a series 
of bins, the number and size of which depend on the kind 
and quantity of materials to be treated; or the raw materials 
may be dumped from the cars into a pit and transferred to 
the bins by a grab bucket. 


Page Six 








































































































































































General Description of a Sintering Plant 


In the case of flue dust, the screening of it is necessary, 
and a considerable quantity of coke is recovered for furnace 
use. 


The bins are fitted with feeders of a special type which are 
driven as a group in synchronism with the sintering ma¬ 
chine. The required composition of the sintering mixture 
is made up by adjusting the feeder gates and the total 
amount of sintering mixture delivered by the feeders is ad¬ 
justed to suit the needs of the sintering machine at various 
speeds. The sintering mixture is carried to and thoroughly 
mixed and moistened in a pug mill or other mixing device 
and is delivered on to the grates of the sintering machine in 
a continuous layer of desired thickness and uniform per¬ 
meability. This continuous layer is moved under an ignition 
burner where the fuel in the upper surface of layer is ignited 
and the charge then continues its movement over a wind box 



A string of pallets showing the ignition burner used 
with blast furnace gas, and the grates. The moisten¬ 
ing of the charge before feeding on to the grates gives 
the necessary cohesion to prevent the material from 
falling through. 


I*age Seven 









American Ore Reclamation Company 



Low Type of Sintering Plant. 





















































Sintering Machines 


connected to a suction fan which draws air down through 
all parts of the charge and the sintering action is progressive 
through the whole depth of the layer down to the grates. 
At the end of the sintering machine the sinter is discharged 
over a grizzly screen which thoroughly separates all fines 
from the sintered material and the fine sinter is returned to 
the sintering mixture to increase its permeability and thereby 
the rate of sintering is increased. 

The whole operation of regulating the feeding of ma¬ 
terial and speed of sintering is controlled by a single lever. 


Sintering Machines 


T YPE A.—Dwight and Lloyd sintering machine shown 
on plate I. has an active grate surface 42" wide by 
25'-6" long with 90 sq. ft. of grate area. This machine 
is adapted to a one or a two blast furnace plant or where a 
small tonnage is required. The capacity of this machine, 
when sintering various materials, based on its performance 
in actual service, is as follows: 


Flue Dust 125 to 150 tons sinter per day of 24 hrs. 

Pyrites Cinder 150 to 175 tons sinter per day of 24 hrs. 

Magnetic Concentrates 175 to 200 tons sinter per day of 24 hrs. 


Type B.—Dwight and Lloyd sintering machine shown 
on Plate II. has an active grate surface 42" wide by 57'-4" 
long with 200 sq. ft. of grate area and has more than double 
the capacity of type A. The capacity of this machine, when 
sintering various materials, based on its performance in 
regular service, is as follows: 

cD 


Flue Dust 
Pyrites Cinder 
.Magnetic Concentrates 


260 to 310 tons sinter per day of 24 hrs. 
300 to 375 tons sinter per day of 24 hrs. 
350 to 400 tons sinter per day of 24 hrs. 


Xype C.—Gayley Two-Strand sintering machine shown 
on plates III. and IV. is the largest capacity sintering ma- 


l’age I\ine 








General Arrangement of Sintering Plant 
Units with Type A Machine. 


£is/re*jN* Plant* ~p*o*e» 


plant. 



Continuous Sintering Layer on Type B Machine. 


Page Ten 




















































































































































































































Sintering Machines 


chine so far developed. It has two parallel tracks of cars 
at the level o( the operating floor. Both of these tracks are 
used for sintering and each has an individual equipment of 
leed hopper, ignition furnace, wind box, and suction fan. 
The parallel tracks are cross connected at each end with 
a combined car and transfer carriage which receives loaded 
cars from the discharge end of one track, dumps and screens 
the sinter, and delivers the empty cars to the feed end of the 
other track. The Two-Strand machine has few working 
parts, and the simplicity of construction coupled with large 
capacity particularly adapts this machine for sintering plants 
required to produce a large tonnage. The cars remain upright 
throughout the cycle of sintering operations except while 
the sinter is being discharged from the car in the transfer 
carriage, and for this reason they are particularly suited to 
the treatment of thick lavers of material from one to four 
feet in depth which gives this machine a special value for 
dehvdrating and sintering Mavari and similar ores. 

j C O J 



Single Machine Plant. Wood Construction. 


Page Eleven 











American Ore Reclamation Company 




The (.ake oi Sinter Ready to Be Discharged From the Machine. 


Page Twelve 



























































Practice and Resirfts 


The Two-Strand sintering machine has an active grate 
surface 48 ' wide by 56'-0" long on each car track or a total 
of 450 sq. ft. of grate area. The capacity of this machine, 
is as follows: 


Flue Dust 
Pyrites Cinder 
Magnetic Concentrates 
Mayari Ore 


550 to 650 tons sinter per day of 24 hrs. 

650 to 750 tons sinter per day of 24 hrs. 

750 to 900 tons sinter per day of 24 hrs. 

1000 tons and upwards per day according 

to the depth of sintering layer. 


Practice and Results 

Flue Dust: 

F LUE dust from different plants may contain from 8% 
to 20% of fuel. The lower percentage is sufficient 
for sintering, and any surplus fuel must be burned off 
and retards the sintering process. This surplus fuel should 
preferably be used to sinter fine ores containing no carbon, 
by mixing them with the flue dust in the sintering charge. 
An increased output can be obtained without appreciable 
increase in operating cost. As an illustration of this, a sin¬ 
tering plant which treated flue dust containing 16% to 18% 
fuel had production increased from 100 tons to 170 tons 
per day by the addition of magnetic ore concentrates. 


FLUE DUST—Dried at 212 Degrees 



Flue 

Flue 

Flue 

Flue 

Analyses: 

Dust Sinter 

Dust Sinter 

Dust Sinter 

Dust Sinter 

Iron 

34.12% 40.67% 

51.15% 57.70% 

50.63% 56.53% 

47.93% 55.02% 

Carbon 

15.00 % .... 

8.15 % .... 

9.69% .... 

14.78% .... 


Flue dust contains volatile matter in addition to carbon. 


SIEVE TEST OF SINTERED FLUE DUST CONTAINING 18% CARBON 


Over 2 in.22.06% 

2 in. to 1 in.21.85% 

1 in. to % in.19.93% 

% in. to % in.34.06% 

Below Vk in. 2.10% 


Total .100.00% 


Page Thirteen 















American Ore Reclamation Company 



Page Fourteen 


Double Inlet Fan. Diameter of Wheel 100 Inches. In Use With a Tyj 

Machine. 












































Practice and Results 


COMPARISON OF PRODUCTS OF DOWN-DRAFT AND 
ROTARY KILN PROCESSES 

Down-Draft Rotary Kiln 


On % in. Mesh.63.84% 26.8% 

On 10 Mesh .35.12% 54.0% 

On 60 Mesh . 0.82% 18.2% 

Below 60 Mesh . 0.22% 1.0% 


Total .100 00% 100.0% 


The screen tests are presented for the purpose only of 
showing the general character of the sinter. 

In practical operations the sinter shipped to the furnace 
from the continuous down-draft machine is passed over a yo 
inch screen, and the hues are returned to the sintering mix¬ 
ture where they are of great advantage through increasing 
the permeability of the charge, and thereby the rate of 
sintering. The admixture of fines to the charge produces a 
firmer sinter. 


Pyrites Cinder and High Sulphur Ore: 

Pyrites cinder and other high sulphur ores are sintered 
and desulphurized in one operation. The cinder contains 
from 1.5% to 5% sulphur, which is reduced to 0.10% to 
0.15% in the sintered product. About 8% to 10% of fuel 
is required. 


Analyses: 

Iron .... 
Sulphur . 


Pyrites Sintered 

Cinder. Product. 

56.28% 61.00% 

4.41% 0.07% 


MIXTURE OF PYRITES CINDER AND FLUE DUST 


Analyses: 

Iron ... 

Sulphur 

Carbon 


Pyrites 

Cinder. 

56.28% 
4.41 % 
0 . 00 % 


Flue 

Dust. 

33.00% 

0.18% 

24.00% 


Average 

Mixture. 

46.97 % 
2.72% 
9.60% 


Sintered 

Product. 

57.10% 

0 . 12 % 


Page Fifteen 















American Ore Reclamation Company 



Page Sixteen 


Type B Machine Set Up in Shop and Loaded With Pig Iron For Testing. 





























Practice and Results 


Magnetic Ore: 


agnetic ore concentrates are ideal for sintering. The 
surfaces of the concentrate grains quickly become pasty and 
adhesion through the mass is obtained more rapidly and at 
a lower temperature than with hematites, and the machine 
can be run faster. If the concentrates contain 1% to 3% 
sulphur the fuel used varies from 5% to 3% respectively.. 


Mayari Ore: 

Mayari ore is more cheaply sintered by the down-draft 
process and provides a material far more desirable for the 
blast furnace than is obtained from the rotary kiln. A 
screen test of sintered Mayari ore made by the continuous 
down-draft process shows as follows: 


Over 2 in. 45.0% 

2 to 1 in. 24.0% 

1 to % in. 18.0% 

Vi to 1/10 in. 6.0% 

Through 10 mesh on 20 . 5.0% 

Through 20 mesh . 2.0% 


100 . 0 % 


The sintering of this kind of ore, which is finely sub¬ 
divided and carries high moisture, is greatly facilitated by 
passing it through a revolving drum to ball the material and 
by mixing with it the sintered fines the ore is materially dried 
and made more permeable to the air draft. In I his shape it 
can be treated in layers with a depth ol 3 to 4 feet. 


Type C, Two-Strand machine, which 
height of sides on the cars, is especially 
purpose. 


permits ol 
adapted to 


any 

j 

this 


rape Seventeen 










American Ore Reclamation Company 



Discharge End of a Two Machine Sintering Plant. 



A Car L oad of Sinter 


Page Eighteen 
























Fuels Used 


Mayari ore requires about 10% of fuel for sintering. 


ses: 

Mayari Ore. 

Sintered Product. 


Natural. Dried. 

A. B. C. 

Iron 

39.50% 48.43% 

54.26% 52.79% 53.97% 

Combined water 

13.50% 

• ••• •••• •••• 

Moisture 

18.50% 

• ••• •••• •••• 


Carbonate Ore: 

Spathic iron or carbonate ore is readily beneficiated by 
sintering. Results obtained by the use of 5% fuel are 
shown as follows: 


Analyses: Carbonate Ore. Sintered Product. 

Iron . 32.87 % 49.70% 

Carbon Dioxide . 27.30% 0.06% 

Sulphur . 1.97% 0.09% 


Mesaba Range Paint Rock: 

The so-called paint rock of the Mesaba Ore Range in 
Minnesota which carries high moisture and combined water, 
is converted into a valuable iron ore when sintered. The 
following result was obtained with 8% fuel. 


Analyses: Paint Rock. 

Natural. Dried. Sintered Product. 

Iron . 40.01% 47.23% 52.70% 

Combined water. 8.98% .... 

Moisture . 15.28% .... .... 


FUELS USED 

C OKE braise and the excess carbon in flue dust are the 
commonly used sintering fuels for treating carbon free 
sintering materials like pyrites cinder, finely divided 
ores and concentrates, etc. Equally good results have been 
obtained from the use of charcoal braise, bituminous screen¬ 
ings, and anthracite dust. 

<D 7 


Cage Nineteen 









Advantages 


All of the fluid fuels ordinarily available are used for 
igniting the sintering charge. The continuous sintering layer 
moving under the ignition furnace at a uniform speed makes 
possible the use of cheap blast furnace gas for ignition fuel 
at blast furnace plants. Where blast furnace gas is not 
available the sintering layer is ignited with natural gas, coke 
oven gas, illuminating gas, or fuel oil as may be economically 
provided. 

ADVANTAGES 

The American Ore Reclamation Company has demon¬ 
strated the following points of advantage to he obtained by 
the continuous method in its process and product: 

PROCESS: 

The continuous process is more economical than the 
intermittent. 

The process converts flue dust and concentrates into a 
superior grade of ore. 

The continuous process uses the cheapest fuel for ig¬ 
nition. 

The sinter is made with the least admixture of fuel. 

Fhe sulphur in the sinter can be reduced to any percent¬ 
age desired. 

High sulphur ores are desulphurized when being sintered, 
while roasting only removes sulphur. 

The sinter is made with less consumption of power than 
required by any other method. 

The production is the greatest per square foot of sinter- 
in g grate area. 

The installation cost per square foot of grate area is 
lower per ton of product than any other process. 


Page Twenty 



Some Users 


I he sintering charge is clumped from sintering machines 
in small units and is easily screened; consequently, no fine 
material is sent to the furnace. 


PRODUCT: 

The sinter contains no silicate of iron. 

The sinter is cellular, not porous. 

Cel hi I ar sinter is quickly reduced in the furnace. 

The sinter is not glazed on the surface. 

The sinter is a first class merchantable ore. 

Sinter causes faster driving and more uniform working, 
and keeps the furnace walls clean. 

Sintered material does not produce (hie dust in the 
furnace. 

The sinter does not disintegrate on exposure to the 
weather. 


Sinter increases production and decreases coke consump¬ 
tion in the furnace. 

Sintered magnetic ore concentrates are the equal of 
natural hematites. 

Sintering removes the objection to the use o( roll scale. 
Flue dust sinter is enriched hv the admixture of fine 

J 

ores, pyrites cinder and roll scale. 

The sinter is of uniform size which produces regularity 

1 Cj j 

in furnace working. 

SOME USERS 

The following companies are using the continuous down¬ 
draft sintering process for iron bearing materials: 

United States Steel Corporation 
Jones and Laughlin Steel Company 
Colorado Fuel and Iron Company 
Alan Wood Iron and Steel Company 

> 

Page Twenty-One ' J 

) > ) 



American Ore Reclamation Company 



The Discharge End of Sintering Machine Showing Screen to Remove 

the Fines. 



/\/ge Twenty-Two 

















Some Users 


E. and G. Brooke Iron Company 
Eastern Steel Company 
Toledo Furnace Company 
Pyrites Company, Limited 
American Sintering Company 
Virginia Iron, Coal and Coke Company 
Oriskany Furnace, Lavino Furnace Company 
Virginia Industrial Chemical Company 
Woodstock Operating Corporation, Alabama 
Low Moor Iron Company of Virginia 
Marting Iron and Steel Company 
Davison Chemical Company 

CONSULTATION 

The American Ore Reclamation Company invites you 
to consult their Engineering Department on sintering prob¬ 
lems who will make a study and submit a preliminary plan 
free of charge. 



A Single Machine Plant in Use For Sintering and 
Desulphurizing Pyrites Cinder. Wood Construction. 


I’age Twenty -Three 











American Ore Reclamation Company 


IN THE CONTINUOUS PROCESS THE WHOLE 
OPERATION IS CONSTANTLY IN VIEW 


Cage Twenty-Four 



I '■ ■: ' : 








Plate I 























































































Plate I 



Type A. Dwight and Lloyd sintering machine 
























































































































































































































































































































































































































Ii sleH 


Plate II 


































































































































Plate II 





































































































































































































































































































































































































































































































































Plate III 













































































































































































Plate III 



OH Ain SPk 
iPfKtx/Z'Sj 


~dHMM 3P£EO PPPffd %■ 72 S 7 


* hA/s* specs ! 
Pa os o> /ZS’Ppn f 


” C HP iff SPBfD 

spppffoi /2jj r.fin. 



1 /, 

— 

V?f 


1 


± 



Plan—Gayley Two-Strand machine plant, 


















































































































































































































































































































































































































































































































































Plate IV 


/ 












































































































































































Plate IV 




Elevation — Gayley Two-Strand machine plant 


Jl ma. 


























































































































































































































































































































































































































































































































































































































































































































